Condensed-phase reactions of O3 with NH3 and NH2OH

Abstract

The reactions of O3 with NH3 and NH2OH were studied in the condensed phase. A yellow ozonide was formed immediately upon the addition of O3 to the NH2OH solid maintained at −190 °C, but the yellow–orange ozonide seen in the NH3 case was not formed until the system was warmed to −170 °C. These ozonides could be reconverted to reactants by photolysis with near ultraviolet light or by heating to −90 °C (NH3+O3−) or −115 °C (NH2OH+O3−).Upon warming the NH3–O3 system to −130 °C, NH4NO3•3NH3 appeared. It started to deamminate at about −105 °C to give NH4NO3. In the NH3–O3 system a second species, tentatively identified as NH2O+HO2−, was also formed at −170 °C. It began to decompose with the evolution of O2 at about −10 °C.In the NH2OH–O3 system, HNO3 was also seen immediately upon addition of O3 to NH2OH. It appeared as NH2OH•HNO3, a hydrogen-bonded complex with NH2OH. At about −100 °C, NH2OH started to anneal and the NH2OH•HNO3 bands grew rapidly and converted to NH3OH+NO3−.There was no evidence of NH2OH as an intermediate in the NH3–O3 system, but since NH2OH reacted so readily with O3, this possibility could not be ruled out. These ozonolysis reactions may be represented as[Formula: see text]and[Formula: see text]